The effect of probing on deceivers and truthtellers

This study examined the effect of probing for additional information on the accuracy of deception detection. One hundred forty-eight experimental interactions were analyzed to see whether deceivers and truthtellers behave differently when probed and whether probing improved deception detection. Probing produced a number of changes in nonverbal behavior, several of which differed between deceivers and truthtellers. Probing may have communicated suspicion or uncertainty; therefore, deceptive sources were motivated to control their nonverbal demeanor to mask deception-related cues and appear truthful. Probing did not improve detection. Instead, probing receivers considered all sources more truthful. It is suggested that suspiciousness and prior knowledge may affect probing's efficacy.